# Homework Help: Spring Help

1. Nov 13, 2008

### redhot209

1. The problem statement, all variables and given/known data
A block of mass 3 kg is hung from a spring, causing it to stretch 6 cm at equilibrium, as shown below. The 3 kg block is then replaced by a 4 kg block, and the new block is released from the position shown below, at which point the spring is unstretched. How far will the 4 kg block fall before its direction is reversed? Hint: for the new block case, the total distance of fall is twice the amplitude of the oscillation. The acceleration of gravity is 9.8 m/s2

2. Relevant equations
My teacher give me this equation. Y2= Y1(M2/M1)

3. The attempt at a solution
Y2=6(3/4) = 8

2. Nov 13, 2008

### physics girl phd

Explain your reasoning. There's lots of fun physics in this problem... and you aren't discussing it! (Your answer also doesn't have units... and you don't seem to know where the equation comes from. I honestly don't either. I'd trace through things I do know, about stretch, energy stored, force...